Triclabendazole: veterinary dose and monograph

At a glance

Drug class

Antiparasitic

Also known as

Fasinex, Egaten

Species with doses

Cattle and Sheep

General dose range

10–12 mg/kg PO single dose — check the species tables for the indication

Routes

PO

Last reviewed

1 October 2026

Indications

• Acute fasciolosis — F. hepatica, F. gigantica
• Sub-acute fasciolosis
• Chronic adult liver fluke (paired with prevention strategy)
• Paramphistomosis (rumen fluke) — variable efficacy

Triclabendazole dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Cattle

• Acute / chronic fasciolosis: Product label (Fasinex 10%): 12 mg/kg PO once. Neither Papich 5e nor Plumb’s has a triclabendazole monograph. Withdrawal periods differ widely between products and countries — follow the local label. Not for lactating dairy cattle producing milk for human consumption.

Goats

• No reference dose for this species: Neither Papich 5e nor Plumb’s has a triclabendazole monograph, and the label source used for this entry covers cattle and sheep only. The previous goat row extrapolated the sheep/cattle dose.

Sheep

• Acute / chronic fasciolosis: Product label (Fasinex 5%): 10 mg/kg PO once; kills early immature to adult flukes. Neither Papich 5e nor Plumb’s has a triclabendazole monograph. Withdrawal differs between products and countries — follow the local label.

Buffalo

No buffalo-specific doses are on file, so buffalo are dosed as cattle.

• Acute / chronic fasciolosis: Product label (Fasinex 10%): 12 mg/kg PO once. Neither Papich 5e nor Plumb’s has a triclabendazole monograph. Withdrawal periods differ widely between products and countries — follow the local label. Not for lactating dairy cattle producing milk for human consumption.

Contraindications

Hypersensitivity. Pregnancy: AVOID in the first trimester of cattle / sheep / goat. Strict withdrawal: cattle 21 d slaughter, 28 d if "dairy" SKU available; sheep 42 d slaughter. Verify regional approval.

Species-specific warnings

Cattle: 12 mg/kg PO single dose. 21 d slaughter withdrawal. Only drug that kills immature fluke — strategic autumn / winter use.

Sheep: 10 mg/kg PO single. 42 d slaughter withdrawal. RESISTANCE rising globally — verify efficacy with faecal egg count post-treatment.

Goats: Extra-label 10–12 mg/kg PO single. Avoid first trimester. Verify withdrawal via FARAD.

Adverse effects

• Transient inappetence
• Soft stool / mild diarrhoea
• Local oral mucosal irritation if drench dose is concentrated

Drug interactions

• Other benzimidazoles (albendazole, fenbendazole): same class — antagonism possible, no benefit to combining for fluke
• Closantel / oxyclozanide: complementary for chronic fluke; rotate or combine on different occasions

Pregnancy and lactation

AVOID first trimester in cattle / sheep / goats. Mid-late pregnancy: extra-label use with caution; product labels vary by jurisdiction.

Monitoring

• Withdrawal strict: 21 d cattle / 42 d sheep slaughter
• Faecal egg counts at 14–21 d post-treatment to confirm efficacy
• Local rotational resistance — monitor with sentinel flock testing if treating annually

Toxicity and overdose

Wide safety margin; therapeutic index >10×. Acute oral overdose: GI upset, anorexia. Hepatotoxicity reported in dogs at very high doses (not a target species).

Clinical pearls

• Acute fasciolosis in sheep: 10 mg/kg PO single dose — only triclabendazole reliably clears the immature flukes causing acute death
• Cattle chronic flukes (autumn calving): 12 mg/kg PO single at housing kills migrating immature stages
• Triclabendazole RESISTANCE is now well-documented globally — rotate with closantel / oxyclozanide for adult flukes (these don't kill immatures, so order matters)
• Strategic deworming: triclabendazole at peak risk (autumn / winter housing); closantel earlier in season for adult-only burdens
• Dose by group weight ÷ heaviest animal to prevent under-dosing (resistance driver)

Mechanism of action

Halogenated benzimidazole pro-drug — converted in the parasite to active sulfoxide and sulfone metabolites. Binds tubulin in the fluke's intestinal cells, disrupting microtubule formation and inhibiting protein synthesis → flukicidal across all life stages (only drug with this breadth). Mechanism is distinct from other benzimidazoles, which explains broader life-stage coverage.

Formulations and products

• Fasinex 5 % oral drench (50 mg/mL) — sheep
• Fasinex 10 % oral drench (100 mg/mL) — cattle
• Fasinex (Elanco (formerly Novartis Animal Health)) — 5 % (50 mg/mL) sheep / 10 % (100 mg/mL) cattle, Oral drench

Storage

15–25 °C protected from light. Shake well before drenching.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other antiparasitics

• Sarolaner
• Selamectin
• Spinosad
• Toltrazuril

Frequently asked questions